Material control apparatus and method



Dec 26, 1933. E. M. HAMHLTON ET AL.

MATERIAL CONTROL APPARATUS AND METHOD Filed Jan. 1 1929 2 Sheets-Sheet 1KO N MW "pg/WWW TL E N w EM WAO T s W m MU E.

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UNITED STA PATENT OFFICE A MATERIAL common APPARATUS AND METHOD EdwardM. Hamilton, Jackson, and scum E. Woodworth, San Francisco, Calif.,assignors to Hamilton, Beauchamp & Woodworth, San

3 Claims.

Our invention relates to regulating apparatus and methods forcontrolling the flow of materials to be mixed or'introduced one into theother, so

as to produce a mixture or compound from predetermined proportions ofeach material.

An object of the invention is to provide an apparatus and method of theabove character which is capable of operating automatically andcontinuously as materials to be mixed or compounded is supplied to thesame.

A further object of the invention is to provide an apparatus and methodof the above character which will be characterized by sensitivity andaccuracy.

Another object of the invention is to provide a novel and relativelysimple combination of elements for attaining the above objects, whichwill be practical, eflicient and reliable in operation.

Referring to the drawings:

Figure 1 is a fragmentary view in elevation showing an apparatusincorporating the present invention.

Figs. 2 and 3 show a modified form of a portion of the apparatus shownin Fig. 1, with certain parts in their extreme positions.

Fig. 4 shows a feeding means for dry material which can be embodied inour invention.

The method of our invention can be best understood from a detaileddescription of our novel apparatus illustrated in the drawings, and itsmode of operation. Referring first to Fig. 1, we have shown a verticalreceptacle 10, which is relatively tall in proportion to its diameter.This receptacle is open at the top to receive a continuous flowingstream of fluid material, from a source represented by outlet 11. Thebottom of receptacle 10 is provided with a discharge outlet 12, providedwith a valve 13, and which forms an orifice thru which material inreceptacle 10 can continually discharge by gravity.

, Receptacle 10 is movable vertically and is carried by suitablecounterbalancing means. Thus the receptacle is shown carried by one endof a beam 14, which in turn is suitably mounted upon a' fulcrum 15. Toform a bias counter to the weight of receptacle 10 and the materialwithin the same, we provide a weight 16 which is connected to the otherend of beam 14.

. As a part of means for controlling the feeding of another material ata rate controlled according to the positioning of receptacle 10, we haveshown a bell crank 1'7 having a fulcrum 18. Operably connected to oneend of bell crank 17, as by means of link 19 and lever 20, we have showna movable rod 21 which is associated with a variable liquid feedingdevice 22 to be presently described in greater detail. If desired, rod21 can also connect with a stylus 23 of suitable recording instrument24, so as to produce upon the recording instrument 24 a suitable graphicgo record of the position of beam 14 and the position of receptacle l0,and which when properly calibrated, may be read in terms of the flow ofmaterial through receptacle 10. Beam 14 can also be provided with apointer 25, which moves 5 adJacent a stationary scale 26 from which therate of flow for any particular instant may be determined.

We may explain at this point that within the range of operation of ourapparatus, as fluid material is continuously supplied to receptacle 10,

a body of this material accumulates within receptacle 10, and by virtueof the gravity head so established, a continuous discharge occurs thruoutlet 12. With a definite rate of flow into the receptacle, a definiteweight of material will be in receptacle 10, to establish a definitehead capable of causing a rate of discharge thru outlet 12 equal to therate of inflow. With an increased rate of flow into the receptacle agreater quantity and a greater head of material is established aboveoutlet 12, to establish a rate of discharge equal to the increased rateof inflow. Likewise with a decreased rate of inflow into the receptaclea lesser head is established above outlet 12, to establish a rate ofdischarge equal to the decreased rate of inflow. Therefore for changesin the rate of flow into receptacle'm the quantity of material withinthis receptacle will vary to effect variations in the weight of thereceptacle and its contents.

With the simple type of beam illustrated, if the effective counterbiasof weight 16 were to have a flxed value, the beam 14 would tip abruptlyat a certain point and remain tipped regardless of further increases inthe rate of flow in the receptacle 10, and likewise when the quantity ofmaterial in receptacle 10 decreased below a certain value, the beam 14would tip back to the original position and so remain. To obviate suchabrupt movements between limiting positions and to effect the resultthat the receptacle will assume various positions of equilibriumresponsive to different rates of flow into the receptacle 10,

the effective counterbias of weight 16 is made automatically variable.Thus as illustrated in the drawing weight 16 is suspended in a buoyantliquid 2'1 so that its effective bias varies as it is moved up and down.To accomplish this we provide a container 28 immediately below and inthe no path of travel of the weight 16, so that the latter will bepartially submerged. In order to provide against the introduction of anyerror due to a receding of the liquid 27 as the weight is raised, or anincrease in the height thereof as the weight is lowered, we provide inconnection with the container 28 an overflow 29 and a continual sourceof, fluid supply thru the pipe 30. This will maintain the level of theliquid in the container 28 substantially constant at all times. With theweight 16 immersed in the liquid 2'7 in this manner; as the beam 14oscillates up and down, it raises weight 16 higher out of the envelopingliquid and proportionately increases its pull on beam 14, or it allowsthe weight to sink deeper therein and thus decrease the pull on beam 14.By such an arrangement beam 14 will assume a condition of equilibrium inaccordance with the quantity or weight of material in the receptacle 10and in accordance with the rate of flow of thematerial into thereceptacle.

From the above, it is evident that the position of pointer 25 upon thescale 26, or in other words the position of the beam 14, will be anindex of the rate of fiow into receptacle 10. If it were desired tocontrol'the feed of the device 22 in proportion to the weight ofmaterial in container 10, this might be done by actuating the bell crank17 directly by the beam 14, but since the discharge from the outlet 12will not be in direct proportion to the head of liquid in container 10,some means is preferably provided to compensate for this fact. We havefound, with a container such as we have illustrated, having an orificein its lower portion forestablishing a gravity discharge therefrom, thatwith a head of 1 foot the discharge through the orifice will be X tonsand that when the head of the liquid has been increased to 6 feet thedischarge through the orifice 12 will be roughly 2X tons. We have,therefore, in order to control the actuation of the feeding device 22 indirect proportion to the discharge through the orifice 12 rather than inproportion to the weight of the material contained in the container 10,provided a segmental gear or rack section 31 upon the balancing arm 14.This segmental gear portion cooperates With a gear 32 secured upon ashaft 33 which carries a cam 34. This cam 34 is adapted to engage aroller 35 carried upon the bell crank 17 and is of such a contour thatthe movement imparted to the bell crank 17 will always be directlyproportional to the discharge of material through the orifice 12 and, asa result, the feeding device 22 will feed material through its dischargeoutlet 36 in amounts which will 'be proportional to the amount ofmaterial being discharged from the orifice 12. Upon close inspection ofthe above aspects of our invention as illustrated in Fig. 1, it will beseen that the ratio between the segmental gear 31 and the gear 32 isroughly 6:1, or, in other words, while the pointer 25 is moving throughan arc of substantially 30, the gear 32 will.move through an arc ofsubstantially 180, thus effecting a movement of the cam 34 which willcause the roller 35 and the bell crank 17 to move between two extremepositions, one closely adjacent the shaft 33 and the other at a pointremoved therefrom corresponding to the longest dimension of the cam.

In the modification of this aspect of our invention illustrated in Figs.2 and 3 of the drawings, we have dispensed with the balancing arm 14 andits attendant mechanism and have substituted therefor a counterbalanc gW ght 36 carried upon a cable 37 which passes over an eccentric drum orsheave 38 and a second sheave 39. The eccentric sheave 38 is so fixedwith respect to the cable 37 that, as the container 10 pulls the weight36 upwardly due to an increase in. the liquids therein, the moment armof the weight-applied forces will be increased directly in proportion tothe increase in weight of material within the container 10 and, sincethe moment arm of the container 10 is fixed; it will be readily seenthat the two will remain in stable equilibrium when there is no. changein weight in the container 10, or, in other Words, since the moment armof the variable container weight is constant, its effect will bevariable weight times constant lever arm; whereas, in the case of theconstant weight with its variable lever arm, the effect will be constantweight times variable lever arm. In this particular embodiment of ourinvention we have dispensed with the segmental gear 31 and itscooperating gear 32 and have mounted a bell crank operating cam 40directly upon a shaft 41 in fixed relation with the eccent-ric sheave 38so that as the sheave 38 is turned by reason of the movement of thecontainer 10, the bell crank 17 will be moved, as previously described,to control the actuation of the auxiliary feeding device 22.

In Fig. 2, the container 10 is shown as having a small amount ofmaterial therein and, as a resuit, the container has been raised by theweight 36 to a position corresponding to its upper limit. Under theseconditions, it will be seen that the moment arms of the applied forcesexerted by the weight 36 are at their lowest value; whereas, in Fig. 3,the container 10 is shown as substantially full of material and, as aresult, is held down into its lowermost position where it has caused theeccentric sheave 38 to rotate and carry the weight suspending portion ofthe cable 37 out from the center thereof so as to increase the momentarm of the forces applied by the weight 36. It is believed from theabove that this embodiment of our invention will be readily understoodand further discussion thereof should therefore not be necessary.

The particular variable material feeding device 22 illustrated in thismodification of our invention is known as the Kraut liquid feeder, whichis the subject of U. S. Patent 1,416,840, dated May 23, 1922. Thisdevice comprises a cylinder 41 having a raised triangular portion 42which revolves horizontally in a bath of the liquid to be deliveredthereby. The cylinder 41 is driven by any suitable means which in thedrawings is illustrated as a belt 43. Arranged adjacent the cylinder 41and adapted to contact with the raised triangular portion 42 is a narrowscoop or scraper 44 that takes off the liquid material, which, by reasonof its consistency, adheres to the surface of the triangular portion.The scraper 44 is supported adjacent the cylinder 41 and movesthereacross from side to side. It is so positioned that as it is thusmoved, it will make contact with the raised triangular portion 42 of thecylinder and scrape from this raised portion a quantity of material orliquid which will be determined by the position at which the scraperengages the triangular surface. By referring to the drawings it will beseen that when the scraper 44 is at the right hand end of the cylinder41, it will be in contact with the surface of the triangular raisedportion 42 for substantially an entire revolution of the cylinder andsince the cylinder, as it revolves in its bath of fit) . adapted forliquid, will be continuously coated with a film of this material, thescraper 44 will remove a streak of this material from the triangularportion during an entire revolution of the cylinder. If the scraper 44is now moved toward the other end of the cylinder, it will contact withthe raised triangular portion 42 for a shorter period of time as thedimension of the triangular surface in the path of the scraper 44 willcontinually decrease until the scraper is moved to the extremeleft handposition of the feeder 22. In this latter position the contact betweenthe scraper 44 and the triangular portion 42 will be only momentary and,as a result, a minimum of material or liquid will be picked up by thescraper 44 and delivered through its discharge outlet 36.

It has in the past been customary to regulate the position of thescraper 44 in a machine of this type by making hand adjustments of thescraper from time to time, as the volume of the pulp being treated mightappear to vary, or on information from the mill man that he intends tovary the flow. Such an arrangement has been found by us to be veryunsatisfactory, be-

cause of the human element so introduced. Ths

is particularly true where a large tonnage of material is being treated,as it is almost impossible to estimate the flow or tonnage passingthrough the mill at any one time. By making the movement of the scraper44 automatic and controlling its movement mechanically so as to producea feeding of material'or liquid from the device 22 in proportion to theflow of material through the receptacle 10, it has been found by us tooperate very satisfactorily and accomplish results in a more reliableand economical manner.

Connected to the scraper 44, we show the discharge outlet 36 which, inaccordance with our present invention, is adapted to convey thismaterial to the material flowing through the outlet 12 to therebyproduce a mixture from predetermined proportions of each material. Inpassing, it should be noted that the material picked up by the scraper44 and discharged through the outlet 36 is preferably conveyed to apoint beyond the receptacle 10 before it is united with the bulk ofmaterial passing therethrough.

In Fig. 4 we have shown apparatus which is use in carrying out ourinvention when it is desired to feed a dry material or substance, as forexample to feed zinc dust precipitant in strict proportion to a flowingstream of gold and silver-bearing cyanide solution. In this case theamount of zinc dust fed is also determined by the fiow or tonnage ofmaterial passing through the receptacle 10, as will hereinafter appear.The apparatus shown in this figure of the drawings is known as a Merrillzinc dust feeder. It should be understood that this feeder per se formsno part of our invention, but is merely shown to illustrate one type ofapparatus whereby our invention can be adapted to the automatic feedingof a dry substance. In this apparatus the dry substance is placed in ahopper 45 which has a discharge outlet 46 from which the substance isconducted to any suitable point. Interposed between the hopper 45 andthe discharge outlet 46 is a screw feeding device 47 which is adapted tobe driven at different speeds to vary the discharge of material throughthe outlet 46 in proportion to the flow of the main solution, as will behereinafter described. A set of stepped pulleys 48 having a belt 49 isprovided for transmitting power from a speed varying mechanism 50. Themechanism 50 is driven at a predetermined speed by means of a. belt 51.and pulley 52. Mounted upon the'shaft of the pulley 52 we provide acone pulley 53 and cooperating therewith a similar pulley 54 whichdrives one of the stepped pulleys 48. A belt 55 passes over the conepulleys 53 and 54. This belt is engaged by a shifting fork 56 mountedupon the rod 21 so that as the beam 14 oscillates,the belt 55 will beshifted by means of the bell crank 17 and the rod 21 to vary the speedof the screw 4'7 and as a result the rate of discharge of materialthrough the outlet 46.

The operation of our invention can best be explained by considering itin conjunction with a practical application thereof. One suchapplication of our device is in the recovery of minerals by theflotation process wherein our device is used to regulate the supply ofoil, tar, or other substances which are to be added to a stream of orepulp on its way to the flotation apparatus. Under these conditions theore pulp is caused to flow through the receptacle 10 which will, byreason of its suspension, assume a certain predetermined position,depending upon the amount of material therein and as, previouslydescribed, this position will determine the amount of oil or othersubstance to be delivered by means of the liquid feeding device 22. As aresult of this arrangement, a predetermined amount of the substance willbe continuously supplied to the flotation apparatus, the amount of thissubstance being in a predetermined proportion to the flow of ore pulp orother material, as previously described.

In applying curinvention to the automatic feeding of zinc dust inmetallurgical processes, operation of our apparatus is as follows:-Themineral bearing cyanide solution to be treated is caused to flow throughthe receptacle 10 and in this case, instead of the rod 21 controllingthe operation of the liquid feeding device 22, it will control theposition of the belt 55 passing over cone pulleys 53 and 54 and thusvary the speed of the screw 47 interposed between the hopper 45 and thedischarge outlet 46 so as to cause a variation in the discharge of zincdust which will be in direct proportion to the flow of themineral-bearing solution passing through the receptacle 10. In the useof zinc dust as a 'precipitant of gold and silver from cyanide solution,the principal variable determining variations in amount of zinc neededis the tonnage of solution. The weight of dissolved gold and silver inthe solution is also a factor, but this usually does not vary over widelimits during the time of operation and in any case is of much less importance than variations in the tonnage of solution flowing from hour tohour. It will thus be seen that by automatically adjusting the feed ofzinc in the desired proportion to the tonnage of solution, a bigimprovement in efilciency will result since there will always besufficient zinc to complete the precipitation 'of whatever amount ofsolution may be flowing at the time and on the other hand there willnever be an overfeed resulting in the waste of zinc and debasing of theprecious metal precipitate.

In addition to providing a novel means of mixing materials inpredetermined proportions, our invention may also be used to determinethe quantity of any material flowing therethrough, whether solid orliquid, so long as it will continually flow by gravity. This assumes,however, that the material being metered will have a substantiallyconstant specific gravity, or in other words,

a constant relation of volume to weight. Such a condition can hardly besaid to exist in the case of ore pulps, but the normal variations indensity are not usually such as would impair the useful,- ness of ourdevice in determining a record of the tonnage flowing from moment tomoment or its average for a 24 hours run. On the other hand, in themetering of solutions when the specific gravity is constant, which isgenerally the case with solutions, the meter readings obtained by ourdevice will be extremely accurate. In carrying out this feature of ourinvention we have provided the recording instrument 24 which may be ofany standard type. The one herein illustrated contains a time controlledrecord sheet upon which the stylus 23 is arranged to move in response tomovements of the balance beam 14. The record sheet of this instrumentcan be graduated to register the tons or pounds passing through thebalanced receptacle per minute or per hour, and, when properlycalibrated with the balance receptacle 10, the graph thus resultingafter a predetermined period will form a record of the total quantitythat has passed through the receptacle l0 irrespective of how the flowmay have fluctuated from hour to hour during that period.

While we have shown the preferred form of our invention as now known tous, it is to be understood that various changes may be made in itsconstruction without departing from the spirit of the invention asdefined in the appended claims.

This application is a continuation in part of our application Serial No.243,170, filed December 28, 1927.

Having thus described our invention, what we claim and desire to secureby Letters Patent 1s 1. In apparatus for effecting a predetermined flowratio between two materials to be mixed or introduced one into theother, one material being fluid in character and flowing continuouslyfrom a source of supply at a flow rate tending to vary betweenrelatively wide limits, a receptacle adapted to receive flow of said onematerial from said source, said receptacle having a fixed lowerdischarge orifice whereby varying masses of said one material will beformed within the receptacle above said orifice in accordance withvaryin rates of flow into the same, and means responsive to the varyingmasses of said one material in said receptacle for controlling the rateof supply of the second material to the first named material.

2. In apparatus for eifecting a predetermined flow ratio between twomaterials to be mixed or introduced one into the other, one materialbeing fluid in character and flowing continuously from a source ofsupply at a flow rate tending to vary between relatively wide limits, areceptacle adapted to receive flow of said one material from saidsource, said receptacle having a fixed lower discharge orifice,counterbalancing means connected to said receptacle and serving tosupport the same for vertical movements, said counterbalancing meansbeing characterized by its application of upward force to saidreceptacle which increases as the receptacle is lowered, whereby thereceptacle assumes various positions of balance for various rates offlow into the same, and means responsive to the positioning of saidreceptacle for controlling the rate of supply of the second material tosaid one material.

3. In a method of controlling the feed of one material with respect tothe flow of another fluid material whereby the two materials areintroduced one into the other according to a predeterminedproportioning, characterized by the use of a movable receptacle having adischarge orifice communicating with its lower portion; said methodincluding the steps of causing a continuous but variable flow of thefluid material into said receptacle, whereby different heads of materialwill be established within said receptacle for different rates of flow,balancing the receptacle at different positions dependent upon thequantity of material within the same, establishing a continuous feed ofsaid one material to the fluid material, and varying said last rate offeed in accordance with the different balanced positions of thereceptacle.

EDWARD M. HAMILTON. SELIM E. WOODWORTH.

